EP 0601888 B1 19981014 - Variable gain RF amplifier with linear gain control
Title (en)
Variable gain RF amplifier with linear gain control
Title (de)
HF-Verstärker mit veränderbarer Verstärkung und linearer Verstärkungssteuerung
Title (fr)
Amplificateur RF à gain variable avec contrÔle de gain linéaire
Publication
Application
Priority
US 98911792 A 19921211
Abstract (en)
[origin: US5307026A] The circuit amplifies an input RF band of signals and exhibits a signal gain in decibels that is a linear function of a logarithmic control signal input. The circuit employs a transistor having an emitter electrode connected through an inductor/resistor combination to a source of common potential. Within a limited band of RF frequencies, the resistor inductor combination appears to be a high impedance. A PIN diode is connected in shunt across the resistor/inductor combination and, in response to a control current, alters its RF resistance. A capacitor is connected across the emitter of the transistor and provides a tuning function so that, at the mid-frequency of the RF band, a resonant tuned circuit results, thereby causing a high value resistive load to appear across the PIN diode. In this manner, linear gain control is achieved by varying a DC control current through the PIN diode.
IPC 1-7
IPC 8 full level
CPC (source: EP US)
H03G 3/3042 (2013.01 - EP US); H03G 7/001 (2013.01 - EP US)
Designated contracting state (EPC)
DE FR GB SE
DOCDB simple family (publication)
US 5307026 A 19940426; DE 69321565 D1 19981119; DE 69321565 T2 19990506; EP 0601888 A2 19940615; EP 0601888 A3 19950614; EP 0601888 B1 19981014
DOCDB simple family (application)
US 98911792 A 19921211; DE 69321565 T 19931210; EP 93310004 A 19931210